The disease wasn’t spreading through the air. It wasn’t spreading between households. Many infections were coming from a single source: an infectious water pump. The disease was a broadcast.

A simplistic definition of “popular” is the quality of being well-liked by most people. But the trouble with this definition is that there are few things that most people like. A book that sells one million copies in a year in the United States is a runaway bestseller—that 99 percent of the country didn’t buy. If ten million U.S. households watch a

In the big picture, the world’s attention is shifting from content that is infrequent, big, and broadcast (i.e., millions of people going to the movies once a week) to content that is frequent, small, and social (i.e., billions of people looking at social media feeds on their own glass-and-pixel displays every few minutes).

Antimetabole

The journalist Steven Levy has called this the “dozen doughnuts” problem. People know they shouldn’t eat doughnuts all day, but if a coworker puts a dozen doughnuts by your desk each afternoon, you might eat until your mouth is caked in sugar. The News Feed, too, can be a daily tabloid—a hyperminiaturized serving of celebrities, quizzes, and other

“The creation of meaning itself is what’s rewarding,” researcher Claudia Muth told me. “An artwork doesn’t have to be ‘easy’ to appeal to its audience.” People like a challenge if they think they can solve it. She calls this moment where disfluency yields to fluency the aesthetic aha.

When I started daydreaming about this book, I spent a lot of time talking to psychologists about fluency—ease of thinking. But as I reflected on my own favorite books and songs and movies, I came to see that what I like most aren’t the easy things, but rather the reward that something difficult has become comprehensible.

Indeed, many of us suffer from ideological “burn-in”—the unfortunate imprinting of biases from stories and exposure.

The number of major-studio films has fallen in the last two decades while marketing costs have soared. In 1980, the major studios spent less than 20 cents on advertising for every $1 they earned at the box office. Now they spend 60 cents to get that buck.